This invention relates to machine engraved identification cards and in particular to a double layered identification card where each layer has an image engraved thereon.
Engraved identification cards and the method of making them utilizing available electronic engraving systems is known. For example, engraved identification cards and the method of making them is disclosed in Oka, et al., U.S. Pat. No. 3,897,964 and Oka, et al., U.S. Pat. No. 3,930,924. Typical electronic systems for engraving cards are disclosed in Noda, et al., U.S. Pat. No. 3,950,608 and Wada et al., U.S. Pat. No. 4,052,739. Utilizing an electronic engraving system such as that described in the Noda and Wada patents, an identification card blank is engraved by making a multiplicity of "V" shaped scores through one opaque colored plastic layer of the card blank into a second different colored opaque plastic layer of the card blank. By altering the depth of the "V" shaped scoring, the width of the region between scores can be continuously varied to generate lignt and dark regions which, when viewed as a composite, form the desired image.
While the above described engraved identification cards provide improved security against forgery, there is a continuing need to further increase security by increasing the difficulty and expense required to forge such identification cards. The present invention provides such an improved security identification card by engraving an identical image on each of two different planar members and then affixing the two planar members together with, for example, a suitable adhesive or a heat bond so that the two engraved images are aligned and appear as a single or composite image to the viewer. A slot or space may be provided between the two engraved planar members with an edge opening to enable insertion of an opaque card between the two engraved images to thereby mask one of the images and prevent the simultaneous viewing of both images. Security is increased because it is necessary to engrave two cards in such a way that the images will align.
Yet another advantage of the double engraved identification card is that the resultant composite image gives the illusion of the depth. Consequently, the viewed composite image appears more realistic than engraved images on prior engraved identification cards.